At present, hollow spaces in process valves, said hollow spaces bordering on seals, particularly as the process valves are used in media flow paths in the food/beverage filling industry, but also in the pharmaceutical and chemical industry, are hermetically sealed, which means that in the case of a proper seal, media flows, such as e.g., product or food flows, do not penetrate into the process valve, nor do any media present in the aforementioned hollow spaces escape out of the process valve and penetrate into the surroundings or into the media flow paths conducted by the process valve.
Among other reasons, one reason for the presence of hollow spaces in process valves, such as, e.g., gaps, that border on seals, is, e.g., the fact that valve disks are often multi-piece and e.g., gaps or hollow spaces can form between valve disk parts that are screwed together. One reason for this multi-piece construction of valve disks is constituted by the fact that this simplifies, e.g., the assembly of ring seals into the retaining groove of the valve disk because the ring seal has to be less strongly deformed during the integration into the retaining groove. Other reasons for the hollow spaces in the valve disk can be due to screwed connections, e.g., of valve disk to valve stem or other process valve components, that are installed for maintenance reasons.
As mentioned, as a rule, the described hollow spaces in process valves are sealed hermetically by sealing elements that seal on both sides.
Described in DE102010003445A1 is, e.g., a process valve as a seat valve having an internal screwed connection of valve parts that seals the interior of the seat valve, particularly the area between the disk parts that borders on the seal, hermetically to the outside.
DE102010030300A1 (see particularly FIG. 1) describes a process valve as a double seat valve having a multi-piece upper valve disk and a multi-piece lower valve disk in which any hollow spaces or gaps that exist between the screwed-together valve disk parts and that border on seals are sealed on both sides with respect to the inside and outside.
Detrimental in the known process valves is, among others factors, that when there are temperature changes, unwanted pressures can form within hermetically chambered hollow spaces that border on the process valve primary seal, which can damage the process valve primary seal or interfere with the function of the same. Moreover, the detection of leakages in the event of a defective primary seal or leaks in the fixing points of the primary seal is hindered.
An object of the present disclosure is consequently to improve process valves, particularly process valves for use in the beverage filling industry, particularly with respect to the sealing behaviour and maintainability.